U.S. Pat. No. 5,894,802 describes a method and apparatus for establishing an isolated position reference in a printing operation. To compensate for discrepancies that can arise over time between isolated position reference signals generated by different regulators, and to avoid problems in the printing process that would result from such discrepancies, the isolated position reference signals generated within the various regulators can be periodically corrected or standardized. In accordance with one of the exemplary embodiments, the isolated position reference signals are corrected or standardized at a time when the print unit chosen as the standard is not being influenced by transient disturbances. This configuration can, for example, be applied to an existing printing press that, due to original design limitations, cannot transmit the same isolated position reference signal to all of its drive units.